ABSTRACT
The light-induced processes performed by photofunctional polymer films are crucial aspects of developing integrated energy storage devices properly. Herein, we report the preparation, characterization, and study of the optical properties of a series of biobased cellulose acetate/azobenzene (CA/Az1) handleable films at different compositions. The photoswitching/back-switching behavior of the samples was investigated using varied LED irradiation sources. Additionally, poly(ethylene glycol) (PEG) was deposited onto cellulose acetate/azobenzene films to study the back-switching process's effect and nature in the fabricated films. Interestingly, the melting enthalpies of PEG before and after being irradiated with blue LED light were 2.5 mJ and 0.8 mJ, respectively. Conveniently, FTIR and UV-visible spectroscopy, thermogravimetry (TGA), contact angle, differential scanning calorimetry (DSC), polarized light microscopy (PLM), and atomic force microscopy (AFM) were used for the characterization of the sample films. Complementarily, theoretical electronic calculations provided a consistent approach to the energetic change in the dihedral angles and non-covalent interaction for the trans and cis isomer in the presence of cellulose acetate monomer. The results of this study revealed that CA/Az1 films are viable photoactive materials displaying handleability attributes with potential uses in harvesting, converting, and storing light energy.
Subject(s)
Light , Ultraviolet Rays , Cellulose/chemistryABSTRACT
Novel biobased films consisting of alginate blends with poly (octanoic acid 2-thiophen-3-yl-ethyl ester) (POTE), a conducting polymer, were prepared by solution casting, and their optical, morphological, thermal, and surface properties were studied. Using UV-visible spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), the effects of tetrahydrofuran solvent vapors on the optical properties and surface morphology of biobased films with different POTE contents were studied. Results indicate that morphological rearrangements of POTE take place during the process of solvent exposure. Specifically, the solvent vapor induced the formation of POTE small crystalline domains, which allows envisioning the potential of tuning UV-visible absorbance and wettability behavior of biobased films. Finally, theoretical electronic calculations (specifically frontier molecular orbitals analysis) provided consistent evidence on POTE's preferential orientation and selectivity toward the THF-vapor medium.
Subject(s)
Alginates/chemistry , Polymers/chemistry , Solvents , Surface Properties , WettabilityABSTRACT
Resumen Introducción: La esofagectomía presenta una alta morbilidad postoperatoria. Sin embargo, las definiciones de las complicaciones son variables. Un grupo multinacional (esophagectomy complications consensus group; ECCG) propuso definiciones estandarizadas. Objetivo: Evaluar las complicaciones postoperatorias en esofagectomía según las definiciones propuestas por el ECCG. Materiales y Método: Realizamos un estudio de cohorte retrospectivo, a partir de una base de datos prospectiva. Se incluyeron pacientes sometidos a una esofagectomía por cáncer entre 1996 y 2018 en un centro. Se aplicaron las definiciones de las complicaciones postoperatorias según el ECCG. Resultados: Se incluyeron 215 pacientes (Hombres 64%; edad 67 [31-82] años). Un 64% presentaban alguna comorbilidad. Existió un predominio de carcinoma escamoso con un 68%. La ubicación tumoral más frecuente fue el tercio inferior del esófago (48%). Se utilizó un abordaje abierto en 74% y mínimamente invasivo en 26%. La morbilidad postoperatoria total fue de 67%. Las complicaciones más frecuentes fueron las respiratorias alcanzando un 27%. En total, un 25% de los pacientes presentó una filtración de la anastomosis esofagogástrica, de las cuales un 24% fueron tipo II (no requirieron una reintervención quirúrgica). Se produjo una paresia de cuerda vocal en 7%, todas tipo I (no requirieron terapia específica). Se presentó una fístula quilosa en 2%, en 1% se trataron con nutrición parenteral (tipo II) y en 1% se realizó una reintervención (tipo III). Conclusión: La esofagectomía se asocia a una alta morbilidad. Las principales complicaciones son las respiratorias y las gastrointestinales. La utilización de las definiciones de consenso permite una estandarización y graduación de las complicaciones.
Introduction: Esophagectomy presents a high postoperative morbidity. However, the definitions used are variable. A multinational group (esophagectomy complications consensus group; ECCG) proposed standardized definitions. Aim: To evaluate postoperative complications in esophagectomy according to the definitions proposed by the ECCG. Materials and Method: We conducted a retrospective cohort study, based on a prospective database. Patients undergoing esophagectomy for cancer between 1996 and 2018 at one center were included. The definitions of postoperative complications according to the ECCG were applied. Results: We included 215 patients (64% men, age 67 [31-82] years). Sixty-four percent had some comorbidity. There was a predominance of squamous carcinoma with 68%. The most frequent tumor location was the lower third of the esophagus (48%). An open approach was used in 74% and minimally invasive in 26%. Total postoperative morbidity was 67%. The most frequent complications were respiratory complications, which reached 27%. The leakage of the esophagogastric anastomosis reached 25%, 24% were type II (did not require surgical reoperation). There was a vocal cord paresis in 7%, all were classified as type I (did not require specific therapy). A chylous fistula was presented in 2%, in 1% they were treated with parenteral nutrition (type II) and in 1% a reoperation was performed (type III). Conclusion: Esophagectomy is associated with a high morbidity. The main complications are respiratory and gastrointestinal. The use of consensus definitions allows standardization and grading of complications.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Postoperative Complications , Esophageal Neoplasms/epidemiology , Esophagectomy/adverse effects , Retrospective Studies , Cohort Studies , MorbidityABSTRACT
Biobased tractable films consisting of blends of chitosan (CS) with polymer bearing carbazole derivatives as pendant groups and fluorene-thiophene as donor-acceptor units (referred to as DA) were prepared, and their optical, morphological and photocatalytic properties were studied. DA was dissolved in tetrahydrofuran (THF) and mixed with an acidified aqueous solution containing chitosan to obtain chitosan/DA (CS/DA) films by solution casting. The fabricated biobased films were characterized using spectroscopic techniques (FT-IR and UV-vis), thermogravimetry, mechanical assays, contact angle analysis, and atomic force microscopy (AFM). The effects of varying DA compositions and the results of exposure to visible-light irradiation of the films were also analyzed. The results indicated the existence of interactions between chitosan and DA and a potentially profitable light-driven response of these biobased films. This behavior was reflected in the optical, topographical, and contact angle properties of the films, which exhibited different characteristics before and after visible-light exposure. Finally, the photocatalytic performance of the biobased films was tested via the decomposition of methyl orange (MO), as a reaction model system. Our results revealed a significant photocatalytic activity (according to biobased film composition, approximately 64 % and 87 % of methyl orange were degraded under continuous visible-light irradiation for 120 min) of the films which is attributed to the combined presence and synergetic effects of the film-forming ability of chitosan and the photoproperties of DA.
Subject(s)
Azo Compounds/chemistry , Chitosan/chemistry , Polymers/chemistry , Light , Microscopy, Atomic Force , Spectroscopy, Fourier Transform Infrared , ThermogravimetryABSTRACT
Wastewater constitutes an alternative water source for the irrigation sector. To fully benefit from it, and reduce possible adverse effects on public health and the environment, we need to look at the regulation of the practice. A prerequisite for this is an institutional analysis, and the points to consider are the institutional mandates. We used the city of Hyderabad, India, as a case study. There, irrigation with wastewater is not supported or recognized, but it happens in practice. It takes place in an indirect and unplanned way. Institutions fail at enforcing regulations, and little attention is given to formalization of the practice. With this article, we aim to untangle the institutional setup, and by doing so, identify the constraints surrounding development of a formal practice. Ultimately, we aim at contributing to the discussion on the agricultural use of wastewater.
Subject(s)
Agriculture/legislation & jurisprudence , Policy Making , Wastewater/analysis , Agriculture/organization & administration , Humans , IndiaSubject(s)
Pharmaceutical Preparations , Self Medication , Adult , Age Factors , Chile , Female , Humans , Male , Self Administration , Sex Factors , Socioeconomic FactorsSubject(s)
Cerebral Cortex , Reflex, Abnormal , Atrophy , Brain Diseases/diagnosis , Humans , Methods , Middle AgedABSTRACT
Contenido: Cap.1 La triangulación aerea espacial. Cap.2 La triangulación aerea con instrumentos de restitución estereoscopica. Cap.3 Control. Cap.4 Ajuste de la triangulación aerea espacial. Cap.5 Comparación de métodos. Cap.6 Costos en triangulación aerea.
